On Fri, 19 Feb 2021 16:37:18 +0000 Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote: > Currently, the UART early address is set indirectly with the --vmm option > and there are only two possible values: if the VMM is qemu (the default), > then the UART address is set to 0x09000000; if the VMM is kvmtool, then the > UART address is set to 0x3f8. > > There several efforts under way to change the kvmtool UART address, and > kvm-unit-tests so far hasn't had mechanism to let the user set a specific > address, which means that the early UART won't be available. > > This situation will only become worse as kvm-unit-tests gains support to > run as an EFI app, as each platform will have their own UART type and > address. > > To address both issues, a new configure option is added, --earlycon. The > syntax and semantics are identical to the kernel parameter with the same > name. Nice one! I like that reusing of an existing scheme. > Specifying this option will overwrite the UART address set by --vmm. > > At the moment, the UART type and register width parameters are ignored > since both qemu's and kvmtool's UART emulation use the same offset for the > TX register and no other registers are used by kvm-unit-tests, but the > parameters will become relevant once EFI support is added. > > Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx> > --- > The kvmtool patches I was referring to are the patches to unify ioport and > MMIO emulation [1] and to allow the user to specify a custom memory layout > for the VM [2] (these patches are very old, but I plan to revive them after > the ioport and MMIO unification series are merged). > > [1] https://lore.kernel.org/kvm/20201210142908.169597-1-andre.przywara@xxxxxxx/T/#t > [2] https://lore.kernel.org/kvm/1569245722-23375-1-git-send-email-alexandru.elisei@xxxxxxx/ > > configure | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/configure b/configure > index cdcd34e94030..d94b92255088 100755 > --- a/configure > +++ b/configure > @@ -26,6 +26,7 @@ errata_force=0 > erratatxt="$srcdir/errata.txt" > host_key_document= > page_size= > +earlycon= > > usage() { > cat <<-EOF > @@ -54,6 +55,17 @@ usage() { > --page-size=PAGE_SIZE > Specify the page size (translation granule) (4k, 16k or > 64k, default is 64k, arm64 only) > + --earlycon=EARLYCON > + Specify the UART name, type and address (optional, arm and > + arm64 only). The specified address will overwrite the UART > + address set by the --vmm option. EARLYCON can be on of (case > + sensitive): > + uart[8250],mmio,ADDR > + Specify an 8250 compatible UART at address ADDR. Supported > + register stride is 8 bit only. > + pl011,mmio,ADDR > + Specify a PL011 compatible UART at address ADDR. Supported > + register stride is 8 bit only. I think the PL011 only ever specified 32-bit register accesses? I just see that we actually do a writeb() for puts, that is not guaranteed to work on a hardware PL011, AFAIK. I guess QEMU just doesn't care ... Looks like we should fix this, maybe we get mmio32 for uart8250 for free, then. The kernel specifies "pl011,mmio32,ADDR" or "pl011,ADDR", so I think we should keep it compatible. "mmio[32]" is pretty much redundant on the PL011 (no port I/O), I think it's just for consistency with the 8250. Can you tweak the routine below to make this optional, and also accept mmio32? Cheers, Andre > EOF > exit 1 > } > @@ -112,6 +124,9 @@ while [[ "$1" = -* ]]; do > --page-size) > page_size="$arg" > ;; > + --earlycon) > + earlycon="$arg" > + ;; > --help) > usage > ;; > @@ -170,6 +185,26 @@ elif [ "$arch" = "arm" ] || [ "$arch" = "arm64" ]; then > echo '--vmm must be one of "qemu" or "kvmtool"!' > usage > fi > + > + if [ "$earlycon" ]; then > + name=$(echo $earlycon|cut -d',' -f1) > + if [ "$name" != "uart" ] && [ "$name" != "uart8250" ] && > + [ "$name" != "pl011" ]; then > + echo "unknown earlycon name: $name" > + usage > + fi > + type=$(echo $earlycon|cut -d',' -f2) > + if [ "$type" != "mmio" ]; then > + echo "unknown earlycon type: $type" > + usage > + fi > + addr=$(echo $earlycon|cut -d',' -f3) > + if [ -z "$addr" ]; then > + echo "missing earlycon address" > + usage > + fi > + arm_uart_early_addr=$addr > + fi > elif [ "$arch" = "ppc64" ]; then > testdir=powerpc > firmware="$testdir/boot_rom.bin"
